Substrate treatment apparatus, substrate holding device, and semiconductor device manufacturing method

ABSTRACT

A nonuniform portion of a film thickness on a substrate owing to effects of a support column, a substrate mounting portion, and the like which constitute a substrate holder is eliminated, and uniformity of the film thickness of the substrate is enhanced.  
     A substrate processing apparatus houses plural wafers (substrates) held on a boat (substrate holder) in a processing chamber, supplying processing gas to the heated processing chamber, thereby performing film-forming processing for the wafers. The boat includes: at least three support columns  15  provided substantially vertically; plural wafer support portions  16  (substrate mounting portions) which are provided at multi-stages on the support columns and mount the plural wafers substantially horizontally at a predetermined interval; and plural ring-like plates  13  arranged on the support columns  15 , and provided substantially horizontally at a predetermined interval with respect to the wafers supported on the wafer support portions  16.

TECHNICAL FIELD

The present invention relates to a substrate processing apparatus, asubstrate holder, and a manufacturing method of a semiconductor device,and particularly, to a substrate processing apparatus, a substrateholder, and a manufacturing method of a semiconductor device, in whichuniformity of a throughput in a surface of a substrate is improved.

BACKGROUND ART

Heretofore, in a vertical CVD apparatus and the like, a boat havingholder plates has been used as a substrate holder which holds pluralwafers (for example, Patent Document 1). As shown in FIG. 15 and FIG.16, the boat has four support columns 32 provided vertically. Thesupport columns are arranged in a range of an approximatesemi-circumference so as to make it possible to load and unload thewafers. Ring-like quartz-made holder plates 33 are welded in ahorizontal attitude at multi-stages to groove portions (not shown)provided on the support columns 32. On an upper surface of each holderplate 33, plural support claw portions 34 are provided as substratemounting portions which mount the wafer thereon.

When wafer processing, for example, film forming is performed on thewafers by using the boat as described above, the quartz-made holderplates 33 uniform a flow of processing gas on surfaces of the wafers,thus making it possible to restrict only a film thickness of ends of thewafers from being thickened. Moreover, the wafers are held on thesupport claw portions 34 provided on the holder plates 33 more insidethan the four support columns 32 arranged on the approximatesemi-circumference. Accordingly, a distance between the columns 32 andthe wafers is lengthened. Therefore, an effect of the support columns 32is reduced, thus making it possible to enhance uniformity of the filmthickness.

Patent Document 1: Japanese Patent Laid-Open Publication No. H11-40509(FIG. 5, FIG. 6, FIG. 7, FIG. 10)

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, even if the conventional boat described above is used, thesupport columns and wafer support portions constitute portions where theflow of the processing gas is nonuniform, and accordingly, the effect ofthese support columns and the wafer support portions cannot beeliminated. Also in a result of the wafer processing, a throughput onthe wafer portions corresponding to the support columns and the wafersupport portions has had a tendency to be decreased.

It is an object of the present invention to provide a substrateprocessing apparatus, a substrate holder, and a manufacturing method ofa semiconductor device, which are capable of solving the above-describedproblems in the conventional technology, eliminating the nonuniformportions of the substrate throughput on the substrate surfaces owing tothe effect from the support columns and the substrate mounting portions,both constituting the substrate holder, and enhancing the uniformity ofthe film thickness in the substrate surfaces.

Means for Solving the Problems

A first invention is a substrate processing apparatus, comprising: asubstrate holder capable of holding plural substrates; a processingchamber which houses the substrates held by the substrate holder;heating means for heating the processing chamber; and gas supplyingmeans for supplying processing gas to the processing chamber heated bythe heating means, thereby processing the substrate, wherein thesubstrate holder includes: at least three support columns providedsubstantially vertically; plural substrate mounting portions which mountthe plural substrates substantially horizontally at a predeterminedinterval, the substrate mounting portions being provided at multi-stageson the support columns; and plural ring-like plates arranged on thesupport columns, and provided substantially horizontally at apredetermined interval with respect to the substrates supported on thesubstrate mounting portions.

The substrates are housed in the processing chamber heated by theheating means in a state of being held on the substrate holder. Here,since the substrate holder which holds the substrates includes the atleast three support columns, the substrate holder can stably hold thesubstrates. Moreover, since the ring-like plates are provided on thesupport columns, a throughput of peripheral edges of the substrates canbe restricted from being increased. Furthermore, the substrate mountingportions are provided not on the ring-like plates but on the supportcolumns, and the support columns and the substrate mounting portions arethus integrated together. Thus, an adverse effect to a substratethroughput, which is given by the support columns and the substratesupport portions, can be reduced. Hence, the in-plane uniformity of thesubstrate throughput can be improved.

Note that the predetermined interval of the “ring-like plates providedsubstantially horizontally at a predetermined interval with respect tothe substrates” includes a value of zero, specifically, includes thatupper surfaces of the substrates and upper surfaces of the ring-likeplates coincide with each other, that is, both of the surfaces becomeflush with each other.

A second invention is the substrate processing apparatus in the firstinvention, wherein the substrate mounting portions are columnar orapproximately semi-columnar in cross section.

Although it is possible to form the substrate mounting portions intoconcave portions by providing grooves on the support columns, thesubstrate mounting portions should be formed into convex portionsprotruded from the support columns. It is preferable that the convexportions be columnar or approximately semi-columnar in cross section. Inthe case of the approximately semi-columnar shape in cross section, anarc side thereof is set as the substrate mounting surfaces. In such away, contact of the substrate mounting portions with the substratesbecomes line contact, and the generation of the particles can bereduced. Note that, in the case of protruding the wafer mountingportions on the support columns, though the substrate mounting portionsmay be formed separately from the support columns and attached onto thesupport columns, the substrate mounting portions may be formedintegrally with the support columns.

A third invention is the substrate processing apparatus in the secondinvention, wherein the substrate mounting portions are inclined downwardtoward an inside of the ring-like plates in a diameter direction. Insuch a way, the contact of the substrate mounting portions with thesubstrates becomes point contact, and the generation of the particlescan be further reduced.

A fourth invention is the substrate processing apparatus in the firstinvention, wherein inner circumferential surfaces of the ring-likeplates, the inner circumferential surfaces being opposite to the supportcolumns, are notched on a periphery of the support columns. When theinner circumferential surfaces of the ring-like plates are notched onthe periphery of the support columns, it becomes easy for the processinggas to flow on the periphery of the support columns, and uniformity ofthe flow of the processing gas to the substrates can be achieved betweenportions where the support columns are present and portions where thesupport columns are not present. Hence, the in-plane uniformity of thesubstrate throughput can be improved.

A fifth invention is the substrate processing apparatus in the fourthinvention, wherein the substrate mounting portions are columnar orapproximately semi-columnar in cross section. In such a way, the contactof the substrate mounting portions with the substrates becomes the linecontact, and the generation of the particles can be reduced.

A sixth invention is the substrate processing apparatus in the fifthinvention, wherein tips of the substrate mounting portions are roundedor chamfered. In such a way, the contact of the substrate mountingportions with the substrates becomes the line contact, and thegeneration of the particles can be reduced.

A seventh invention is the substrate processing apparatus in the sixthinvention, wherein the substrate mounting portions are inclined downwardtoward an inside of the ring-like plates in a diameter direction. Insuch a way, the contact of the substrate mounting portions with thesubstrates becomes the point contact, and the generation of theparticles can be further reduced.

An eighth invention is the substrate processing apparatus in the fourthinvention, wherein the support columns are composed into anapproximately semi-columnar shape in cross section, and the substratemounting portions are protruded on a chord side of the support columns.In such a way, interference of the gas flow, which is caused by thesupport columns and the substrate mounting portions, can be reduced, anda flow rate of the processing gas flowing in the vicinities of thesupport columns and the substrate mounting portions can be increased.Note that the support columns may be composed into a half-pipe shape,and that the substrate mounting portions may be protruded on a concaveportion side thereof.

A ninth invention is the substrate processing apparatus in the eighthinvention, wherein, on the chord side, an inside thereof in a diameterdirection of the ring-like plates is scooped out. In such a way, theflow rate of the processing gas flowing in the vicinities of the supportcolumns and the substrate mounting portions can be further increased.

A tenth invention is the substrate processing apparatus in the fourthinvention, wherein the support columns are provided more inside thanouter circumferences of the ring-like plates. In such a way, it is madepossible to maintain the gap between the support columns and theprocessing chamber far more appropriately.

An eleventh invention is a substrate processing apparatus, comprising: asubstrate holder capable of holding plural substrates; a processingchamber which houses the substrates held by the substrate holder;heating means for heating the processing chamber; and gas supplyingmeans for supplying processing gas to the processing chamber heated bythe heating means, thereby processing the substrate, wherein thesubstrate holder includes: at least three support columns providedsubstantially vertically; and plural ring-like plates which surround theat least three support columns, are provided at multi-stages on thesupport columns, and are provided substantially horizontally at apredetermined interval with respect to the substrates held by thesubstrate holder, and inner circumferential surfaces of the ring-likeplates, the inner circumferential surfaces being opposite to the supportcolumns, are notched on a periphery of the support columns.

Here, since the substrate holder which holds the substrates includes theat least three support columns, the substrate holder can stably hold thesubstrates. Moreover, since the ring-like plates are provided on thesupport columns, the throughput of the peripheral edges of thesubstrates can be restricted from being increased. Furthermore, sincethe inner circumferential surfaces of the ring-like plates are notchedon the periphery of the support columns, it becomes easy for theprocessing gas to flow on the periphery of the support columns, and theuniformity of the flow of the processing gas to the substrates can beachieved between the portions where the support columns are present andthe portions where the support columns are not present. Hence, thein-plane uniformity of the substrate throughput can be improved.

Note that the predetermined interval of the “ring-like plates providedsubstantially horizontally at a predetermined interval with respect tothe substrates” includes the value of zero, specifically, includes thatthe upper surfaces of the substrates and the upper surfaces of thering-like plates coincide with each other, that is, both of the surfacesbecome flush with each other.

Moreover, in the eleventh invention, holes for fitting the ring-likeplates to the support columns are provided, the holes are opened to theinner circumferential surface side of the ring-like plates, and theinner circumferential surfaces of the ring-like plates may be thusnotched on the periphery of the support columns. Moreover, the substratemounting portions in the substrate holder capable of holding the pluralsubstrates may be provided either on the support columns or on thering-like plates.

A twelfth invention is the substrate processing apparatus in theeleventh invention, wherein the support columns are composed into anapproximately semi-columnar shape in cross section, and the substratemounting portions are protruded on a chord side of the support columns.In such a way, the interference of the gas flow, which is caused by thesupport columns and the substrate mounting portions, can be reduced, andthe flow rate of the processing gas flowing in the vicinities of thesupport columns and the substrate mounting portions can be increased.

A thirteenth invention is the substrate processing apparatus in theeleventh invention, wherein the support columns are provided more insidethan outer circumferences of the ring-like plates. In such a way, it ismade possible to maintain the gap between the support columns and theprocessing chamber far more appropriately.

A fourteenth invention is the substrate processing apparatus in thetwelfth invention, wherein, on the chord side, an inside thereof in adiameter direction of the ring-like plates is scooped out. In such away, the flow rate of the processing gas flowing in the vicinities ofthe support columns and the substrate mounting portions can be furtherincreased.

A fifteenth invention is a substrate holder capable of holding pluralsubstrates, comprising: at least three support columns providedsubstantially vertically; plural substrate mounting portions which mountthe plural substrates substantially horizontally at a predeterminedinterval, the substrate mounting portions being provided at multi-stageson the support columns; and plural ring-like plates arranged on thesupport columns, and provided substantially horizontally at apredetermined interval with respect to the substrates supported on thesubstrate mounting portions.

Since the substrate holder which holds the substrates includes the atleast three support columns, the substrate holder can stably hold thesubstrates. Moreover, since the ring-like plates are provided on thesupport columns, the throughput of the peripheral edges of thesubstrates can be restricted from being increased. Furthermore, thesubstrate mounting portions are provided not on the ring-like plates buton the support columns, and the support columns and the substratemounting portions are thus integrated together. Thus, the adverse effectto the substrate throughput, which is given by the support columns andthe substrate support portions, can be reduced. Hence, the in-planeuniformity of the substrate throughput can be improved.

Note that the predetermined interval of the “ring-like plates providedsubstantially horizontally at a predetermined interval with respect tothe substrates” includes the value of zero, specifically, includes thatthe upper surfaces of the substrates and the upper surfaces of thering-like plates coincide with each other, that is, both of the surfacesbecome flush with each other.

A sixteenth invention is the substrate holder in the fifteenthinvention, wherein inner circumferential surfaces of the ring-likeplates, the inner circumferential surfaces being opposite to the supportcolumns, are notched on a periphery of the support columns. In such away, it becomes easy for the processing gas to flow on the periphery ofthe support columns, and the uniformity of the flow of the processinggas to the substrates can be achieved between the portions where thesupport columns are present and the portions where the support columnsare not present.

A seventeenth invention is a substrate holder capable of holding pluralsubstrates, comprising: at least three support columns providedsubstantially vertically; and plural ring-like plates which surround theat least three support columns, are provided at multi-stages on thesupport columns, and are provided substantially horizontally at apredetermined interval with respect to the substrates held by thesubstrate holder, wherein inner circumferential surfaces of thering-like plates, the inner circumferential surfaces being opposite tothe support columns, are notched on a periphery of the support columns.

Since the substrate holder which holds the substrates includes the atleast three support columns, the substrate holder can stably hold thesubstrates. Moreover, since the ring-like plates are provided on thesupport columns, the throughput of the peripheral edges of thesubstrates can be restricted from being increased. Furthermore, sincethe inner circumferential surfaces of the ring-like plates are notchedon the periphery of the support columns, it becomes easy for theprocessing gas to flow on the periphery of the support columns, and theuniformity of the flow of the processing gas to the substrates can beachieved between the portions where the support columns are present andthe portions where the support columns are not present. Hence, thein-plane uniformity of the substrate throughput can be improved.

Note that the predetermined interval of the “ring-like plates providedsubstantially horizontally at a predetermined interval with respect tothe substrates” includes a value of zero, specifically, includes thatthe upper surfaces of the substrates and the upper surfaces of thering-like plates coincide with each other, that is, both of the surfacesbecome flush with each other.

An eleventh invention is a method of manufacturing a semiconductordevice, the method using a substrate processing apparatus including: asubstrate holder capable of holding plural substrates; a processingchamber which houses the substrates held by the substrate holder;heating means for heating the processing chamber; and gas supplyingmeans for supplying processing gas to the processing chamber heated bythe heating means, thereby processing the substrate, in which thesubstrate holder includes: at least three support columns providedsubstantially vertically; plural substrate mounting portions which mountthe plural substrates substantially horizontally at a predeterminedinterval, the substrate mounting portions being provided at multi-stageson the support columns; and plural ring-like plates arranged on thesupport columns, and provided substantially horizontally at apredetermined interval with respect to the substrates supported on thesubstrate mounting portions, the method comprising the steps of:mounting the substrates on the substrate mounting portions of thesubstrate holder; carrying the substrates mounted on the substratemounting portions of the substrate holder into the processing chamber;heating the processing chamber by the heating means; and supplying theprocessing gas to the heated processing chamber, thereby processing thesubstrate.

The plural substrates are mounted on the substrate mounting portions,thereby being held on the substrate holder. The substrate holder onwhich the plural substrates are held is carried into the processingchamber. The processing chamber is heated by the heating means, theprocessing gas is supplied to the heated processing chamber, and theplural substrates held on the substrate holder are processed. Here,since the substrate holder which holds the substrates includes the atleast three support columns, the substrate holder can stably hold thesubstrates. Moreover, since the ring-like plates are provided on thesupport columns, the throughput of the peripheral edges of thesubstrates can be restricted from being increased. Furthermore, thesubstrate mounting portions are provided not on the ring-like plates buton the support columns, and the support columns and the substratemounting portions are thus integrated together. Thus, the adverse effectto the substrate throughput, which is given by the support columns andthe substrate support portions, can be reduced. Hence, the in-planeuniformity of the substrate throughput can be improved.

Note that the predetermined interval of the “ring-like plates providedsubstantially horizontally at a predetermined interval with respect tothe substrates” includes the value of zero, specifically, includes thatthe upper surfaces of the substrates and the upper surfaces of thering-like plates coincide with each other, that is, both of the surfacesbecome flush with each other.

Effect of the Invention

According to the present invention, nonuniform portions of the substratethroughput in the substrate surfaces owing to the effects of the supportcolumns, the substrate mounting portions, and the like which constitutethe substrate holder can be eliminated, and the uniformity of the filmthickness in the substrate surfaces can be enhanced. Hence, enhancementsof yield and quality in manufacture of the semiconductor device can beachieved.

BEST MODE FOR CARRYING OUT THE INVENTION

A description will be made below of an embodiment in which a substrateprocessing apparatus, a substrate holder, and a manufacturing method ofa semiconductor device according to the present invention are applied toa semiconductor manufacturing apparatus including a vertical furnace.

FIG. 11 is a schematic view of the semiconductor manufacturing apparatusincluding the vertical furnace, and FIG. 12 is a cross-sectional view ofa reduced-pressure CVD processing furnace as the vertical furnace. Asshown in FIG. 11, a cassette loader 6 is located on a front side in aninside of a cabinet 10, and a cassette shelf 1 is provided on a backside of the cassette loader 6. A buffer cassette shelf 7 is providedabove the cassette shelf 1, and a wafer transfer machine 2 is providedon a back side of the cassette shelf 1. A boat elevator 8 which elevatesand lowers a boat 217 is provided on a back side of the wafer transfermachine 2, and a vertical furnace 5 is provided above the boat elevator8.

As shown in FIG. 12, the vertical furnace 5 includes an outer pipe(hereinafter, an outer tube 205), and an inner pipe (hereinafter, aninner tube 204). The outer tube 205 is formed of a heat resistantmaterial such as, for example, quarts (SiO₂) and the like, and has acylindrical form in which an upper end is closed and an opening isprovided on a lower end. The inner tube 204 has a cylindrical form inwhich openings are provided on both of upper and lower ends, and isdisposed in the outer tube 205 coaxially therewith. A space between theouter tube 205 and the inner tube 204 forms a tubular space 250. Gaselevated from the upper opening of the inner tube 204 passes through thetubular space 250, and is emitted from an exhaust pipe 231.

A manifold 209 formed of, for example, stainless steel and the like isengaged with the lower ends of the outer tube 205 and the inner tube204, and the outer tube 205 and the inner tube 204 are held on themanifold 209. The manifold 209 is fixed to holding means (hereinafter, aheater base 251). Annular flanges are individually provided on the lowerend of the outer tube 205 and an upper opening end of the manifold 209.A hermetically sealing member (hereinafter, an O-ring 220) is disposedbetween these flanges, and both of the flanges are hermetically sealed.

Onto a lower opening of the manifold 209, a disk-like cap member(hereinafter, a seal cap 219) formed of, for example, stainless steeland the like is attached through the O-ring 220 so as to be capable ofhermetically sealing the lower opening and to be freely detachabletherefrom. To the seal cap 219, a gas supply pipe 232 as gas supplyingmeans is provided so as to penetrate therethrough. By the gas supplypipe 232, the processing gas is supplied into the inner tube 204. Thegas supply pipe 232 is coupled to flow rate controlling means(hereinafter, a mass flow controller (MFC) 241) for the gas, and the MFC241 is connected to a gas flow rate control unit 122 of a secondcontrolling computer 120, thus making it possible to control a flow rateof the processing gas to be supplied at a predetermined value.

To an upper portion of the manifold 209, there is connected a gasexhaust pipe 231 to which a pressure regulator (including an APC, and anN2 ballast controller, and hereinafter, referred to as an APC 242) andan exhaust device (hereinafter, a vacuum pump 246) are coupled. Thus,the gas flowing in the tubular space 250 between the outer tube 205 andthe inner tube 204 is emitted, and a pressure in the outer tube 205 iscontrolled by the APC 242. Thus, the pressure is detected by pressuredetecting means (hereinafter, a pressure sensor 245) so as to allow thegas to be set at a reduced atmosphere with a predetermined pressure, andis controlled by a pressure control unit 123 of the second controllingcomputer 120.

Rotating means (hereinafter, a rotation shaft 254) is coupled to theseal cap 219, and by the rotation shaft 254, a substrate holder(hereinafter, a boat 217) and wafers 200 held on the boat 217 arerotated. Moreover, the seal cap 219 is coupled to elevating means(hereinafter, a boat elevator 225), which elevates and falls the boat217. Speeds of the rotation shaft 254 and the boat elevator 225 arecontrolled so as to be set at predetermined values by a drive controlunit 124 of the second controlling computer 120.

On an outer circumference of the outer tube 205, heating means(hereinafter, a heater 207) is disposed coaxially therewith. The heater207 detects temperature in the outer tube 205 by temperature detectingmeans (hereinafter, a thermocouple 263) so as to set the temperature ata predetermined processing temperature, and controls the temperature bya temperature control unit 121 of the second controlling computer 120.The above-described inner tube 204, outer tube 205 and manifold 209constitute a processing chamber 201 for housing and processing thewafers 200 supported on the boat 217.

The above-described second controlling computer 120 is controlled by afirst controlling computer 110 in a centralized manner. The firstcontrolling computer 110 and the second controlling computer 120 areconnected to each other through respective interfaces 111 and 125thereof.

FIG. 14 is a view showing a hardware configuration of the firstcontrolling computer 110 shown in FIG. 12. As shown in FIG. 14, thecontrolling computer 110 is composed of a CPU 300, a memory 304, adisplay/input unit 302 including keys, a display device, and the like,and a recording unit 306 such as a CD device and a HDD device. Recordingis performed in the recording unit 306 through a recording medium 308.The controlling computer 110 includes constituents as a computer, whichexecute a program and the like for controlling the semiconductormanufacturing apparatus, and allow the program and the like to performthe processing for the wafers.

Note that the second controlling computer 120 also includes one or moresets of constituents similar to those of the first controlling computer110. Moreover, in the second controlling computer 120, theabove-described temperature control unit 121, gas flow rate control unit122, pressure control unit 123, and drive control unit 124 may beindividually composed singly, or two or more thereof may be combined.Alternatively, the above-described units may make various formations.

A description will be made of an example of a reduced-pressure CVDprocessing method by the processing furnace shown in FIG. 12. First, theboat 217 is lowered by the boat elevator 225. The plural wafers 200 areheld on the boat 217. Subsequently, the temperature in the processingchamber 201 is set at the predetermined processing temperature whileheating the processing chamber 201 by the heater 207. The processingchamber 201 is filled with inert gas in advance by the MFC 241 connectedto the gas supply pipe 232, and by the boat elevator 225, the boat 217is elevated and transferred into the processing chamber 201. Then, innertemperature of the processing chamber 201 is maintained at thepredetermined processing temperature. After the inside of the processingchamber 201 is exhausted to a predetermined vacuum state, the boat 217and the wafers 200 held on the boat 217 are rotated by the rotationshaft 254. Simultaneously, the processing gas is supplied from the gassupply pipe 232. In the inner tube 204, the supplied processing gasflows upward from a bottom thereof, and is supplied uniformly to thewafers 200.

The inside of the processing chamber 201 under the reduced-pressure CVDprocessing is exhausted through the exhaust pipe 231, the pressurethereof is controlled by the APC 242 so as to obtain predeterminedvacuum, and the reduced-pressure CVD processing is performed, thusforming thin films on the wafers 200.

When the reduced-pressure CVD processing is finished as described above,the inert gas is substituted for the gas in the processing chamber 201and the pressure is set at normal pressure in order to proceed to thereduced-pressure CVD processing for the next wafers 200. Thereafter, theboat 217 is lowered by the boat elevator 225, and the boat 217 and thealready processed wafers 200 are taken out of the processing chamber201. The processed wafers 200 on the boat 217 taken out of theprocessing chamber 201 are exchanged with unprocessed wafers 200. Theunprocessed wafers 200 are elevated in the processing chamber 201 onemore time in a similar way to the above, and are subjected to thereduced-pressure CVD processing.

In order to enhance in-plane uniformity of thickness of thin filmsformed on the wafers 200 in the above-described reduced-pressure CVDprocessing, preferably, support columns constituting the boat 217 shouldbe adapted not to run over ring-like plates in the case of using a boatwith a structure in which the ring-like plates are provided on thesupport columns, which is similar to that shown in FIG. 15 and FIG. 16.Moreover, since the boat 217 is rotated by the rotation shaft 254, inparticular, the support columns are provided more inside than outercircumferences of the ring-like plates, thus making it possible to moreappropriately maintain a gap between the boat 217 and the inner tube 204in the case of the rotation. Thus, generation of particles, and the likeowing to rubbing of the support columns and an inner wall of the innertube 204 can be avoided. Hence, the support columns should not run overthe ring-like plates, and a contour of the ring-like plates should befree from deformation and projection.

Incidentally, in the above-described processing furnace, the descriptionhas been made of the case where the processing gas flows in the innertube 204 upward from the bottom thereof. However, the flow of theprocessing gas is not limited to this. For example, there is also a casewhere the processing gas flows across the inner tube 204.

FIG. 13 is an explanatory view of main portions of the processingfurnace in such a case where the processing gas flows across the innertube 204. Here, the inner tube 204 is composed such that the upper endthereof is closed, and that a slit-like opening 214 is provided on oneside surface thereof.

A description will be made of the gas flow in the inner tube 204. FIG.13(a) shows a case where the gap t between the inner tube 204 and anouter diameter of the boat 217 is small, and FIG. 13(b) shows a casewhere the gap is large.

As shown in FIG. 13(a), in the case of jetting the processing gas from adirection parallel to the surfaces of the wafers 200, it is necessary tominimize the gap t between the inner tube 204 and the outer diameter ofthe boat 217 in order to uniform the flow of the processing gas. This isfor the following purpose. After the processing gas is introduced alongring-like plates 13 and passes through the surfaces of the wafers 200,the processing gas should be led out of the slit-like openings 214provided on the inner tube 204 and exhausted from the space 250 whilebeing left as it is without receiving disturbance on the flow thereof.As opposed to this, when the gap t is large as shown in FIG. 13(b), adown flow 218 as shown by an arrow occurs in a space 249 between theinner tube 204 and the outer diameter of the boat 217, and the exhaustbecomes nonuniform in the vertical direction in the processing chamber201, thus affecting the uniformity of the film thickness of the wafers200.

Also in this case, in order to minimize the above-described gap t and toenhance the uniformity of the film thickness in the wafer surfaces, thesupport columns constituting the boat 217 should not run over thering-like plates 13. Moreover, the support columns should not run over,or the contour of the ring-like plates 13 should not be deformed.

In this connection, in the boat 217 of this embodiment, in order to copewith requirements as described above no matter whether the processinggas flows in the inner tube 204 upward from the bottom or passes acrossthe inner tube 204 depending on the structure of the inner tube 204,wafer support portions as substrate support portions are fixedlyattached not onto the ring-like plates 13 but directly onto the supportcolumns 15. Moreover, inner circumferential surfaces of the ring-likeplates 13, which are opposite to the support columns, are notched on theperiphery of the support columns. Thus, the uniformity of the filmthickness in the wafer surfaces can be enhanced in the semiconductormanufacturing apparatus. In particular, in a batch type semiconductormanufacturing apparatus including such a vertical furnace as in thisembodiment, requirements for enhancement of a film-forming rate(enhancement of a deposition rate) and enhancement of wafer quality canalso be coped with.

A description will be made below of the boat of this embodiment by usingFIG. 1 and FIG. 2. FIG. 1 is an explanatory view of one ring-like plate:FIG. 1(a) is a side view of main portions of the boat, in whichattention is paid to one ring-like plate; and FIG. 1(b) is a plan viewincluding the support columns. FIG. 2 is an entire configuration view ofthe boat.

The boat 217 is made of, for example, quartz, and as shown in FIG. 2,includes a bottom disk 17 and a top disk 11 as two parallel plates, andplural, for example, three support columns 15 provided substantiallyvertically between the bottom disk 17 and the top disk 11. The supportcolumns 15 have a columnar shape. In order to stably and simply supportthe ring-like plates 13, it is particularly preferable that the numberof support columns 15 be three; however, the number may be more thanthree.

The three support columns 15 are arrayed and fixed approximatelysemi-circularly onto the bottom disk 17. The top plate 11 is fixed onupper ends of the three support columns 15. On center portions of thebottom disk 17 and the top disk 11, circular holes 12 and 14 forfacilitating the processing gas to enter into the boat 217 areindividually formed. Between the bottom disk 17 and the top disk 11, theplural ring-like plates 13 provided at a predetermined interval in asubstantially horizontal attitude at multi-stages are fixedly attachedonto the support columns 15.

On each of the support columns 15, plural wafer support portions 16capable of mounting the plural wafers 200 substantially horizontally ata predetermined interval in the vertical direction are protruded atmulti-stages. As shown in FIG. 1, each of the wafer support portions 16has a columnar shape, and is protruded toward the center of the boat217, that is, the center of the ring-like plate 13. In this case, in thesupport column 15, the wafer support portion 16 is provided for each ofthe wafers 200. Specifically, three wafer support portions 16 areprotruded at one stage. By supporting the outer circumference of thewafer 200 on the three wafer support portions 16 thus protruded, thewafer 200 is mounted thereon. It is preferable that the wafer supportportions 16 maintain horizontalness thereof. By maintaining thehorizontalness, such interference that each wafer contacts the wafersupport portion 16 can be avoided when the wafer is carried, and inaddition, a uniform gas flow can be ensured on each wafer in a statewhere the wafers are mounted on the boat 217.

The above-described ring-like plates 13 are arranged below positions ofthe support columns 15, where the respective wafer support portions 16are arranged, and are provided substantially horizontally at apredetermined interval with respect to the wafers 200 supported by thewafer support portions 16. Each ring-like plate 13 is formed into asubstantial circular shape in which the center is opened, and surroundsthe three support columns 15 by housing the three support columns 15 onthe inner circumferential surface of the ring-like plate 13. As in thisembodiment, the ring formed substantially circularly over the overallcircumference of the wafer is provided, thus making it possible toreduce the tendency that the film thickness of the peripheral edge ofthe wafer is thickened.

On the inner circumferential surface of the ring-like plate 13, which isopposite to the support columns 15, or on the inner circumferentialsurface thereof close to the support columns 15, or on the innercircumferential surface thereof proximate to the support columns 15,notches 20 formed by notching the ring-like plate 13 on the periphery ofthe support columns 15 are formed for the purpose of inserting the threesupport columns 15 into the ring-like plate 13. As shown in FIG. 1(b),totally three notches 20 are formed, which are one on an opposite sideto a loading/unloading side of the wafer on a center line 21 of thering-like plate 13, and two at symmetrical positions with respect to thecenter line 21. The notches 20 are formed from the inside of thering-like plate 13 so that the support columns 15 can be housed within aplate width of the ring-like plate 13. The notches 20 do not reach theoutside of the ring-like plate 13. Moreover, in order to reduce anadverse effect to the film thickness, it is preferable that the supportcolumns 15 be provided within the width between the inner and outerdiameters of the ring-like plates 13. Moreover, since the boat 217 isrotated by the rotation shaft 254, in particular, the support columnsare provided on the inside of the ring-like plate rather than on theoutside thereof, thus making it possible to more appropriately maintainthe gap between boat 217 and the inner tube 204 in the case of therotation. Thus, the generation of the particles, and the like owing tothe rubbing of the support columns and the inner wall of the inner tube204 can be avoided. Hence, the support columns should not run over thering-like plate, and the contour of the ring-like plate should be freefrom the deformation and the projection.

FIG. 3 is a perspective view showing the periphery of the support column15 in the vicinity of the above-described wafer support portion 16. Asalready described, the wafer support portion 16 is protruded on thesupport column 15. Here, the wafer support portion 16 as a separatemember from the support column 15 is fixedly attached onto the supportcolumn 15, and the wafer support portion 16 is protruded on the supportcolumn 15. The ring-like plate 13 is disposed below the position of thesupport column 15, where the wafer support portion 16 is arranged, andthe ring-plate 13 is provided substantially horizontally at thepredetermined interval with respect to the wafer supported on the wafersupport portion 16.

Moreover, the notch 20 is formed on the periphery of the support column15 on the inner circumferential surface of the ring-like plate 13. Thenotch 20 is composed of a semi-circular or approximately semi-circularfitting portion as a hole into which the support column 15 is fitted,and an opening 20 b which opens the fitting portion to the innercircumferential direction of the ring-like plate 13. When the opening 20is viewed from the above and the wafer support portion 16 is projectedon the opening 20 b in a state where the support column 15 is fitted tothe fitting portion 20 a, it is preferable that the opening 20 b behoused in the center of the opening 20 b, and that an open width of theopening 20 b be larger than the width of the wafer support portion 16.When the opening 20 b which opens in the inner circumferential directionof the ring-like plate 13 is provided on the notch 20 as describedabove, the gas which has hit on the wafer support portion 16 from theabove goes around both sides of the wafer support portion 16, anddirectly flows downward through the opening portion 20 b. Accordingly,turbulence becomes difficult to occur on the wafer support portion 16.Hence, a difference in flow of the processing gas is eliminated betweena portion having the support column 15 with the wafer support portionand the other portion. In particular, as in the illustrated example, itis preferable that the opening 20 b open in a fan shape to the innercircumferential surface side. This is because, when the opening 20 opensin the fan shape, the turbulence becomes more difficult to occur on thewafer support portion 16, and the difference in flow of the processingis eliminated more between the portion having the support column 15 withthe wafer support portion and the other portion.

Moreover, as shown in FIG. 5, a tip of the wafer support portion 16formed into the columnar shape should be rounded (R) or chamfered (C).Moreover, with regard to a fixing angle of the columnar wafer supportportion 16 to the support column 15, each wafer support portion 16 maybe provided parallel to the wafer 200 as shown in FIG. 5, or each wafersupport portion 16 may be fixed to the support column 15 so as to beinclined downward by θ.

Note that FIG. 3 shows an embodiment in which the columnar wafer supportportion 16 separate from the support column 15 is fixedly attached tothe support column 15. However, the present invention is not limited tothis. As shown in FIG. 4, the support column 15 and the wafer supportportion 16 may be formed into an integral member 18. In this case, inorder to facilitate a process thereof, the wafer support portion 16should be formed not into the columnar shape but into an approximatelytriangular plate shape, a base side of the approximate triangle shouldbe integrated with the support column 15, and an apex side of theapproximate triangle should be directed to the inside of the ring-likeplate 13 in the diameter direction. Moreover, the wafer support portion16 is not only parallel to the wafer but also may be processed so as tobe inclined downward by θ in a similar way to that in FIG. 6.

In order to fabricate the above-described boat 217, here, the ring-likeplates 13 are temporarily fixed horizontally at the multi-stages byusing a jig (not shown). There is adopted a method of fitting andwelding, to the notches 20, the three support columns 15 from the insideof the temporarily fixed ring-like plates 13 at the multi-stages.Specifically, the plural ring-like plates 13 on which the notches 20 areformed are prepared. The plural ring-like plates 13 are temporarilyfixed by the jig in a state of being aligned and stacked so that therespective notches 20 can vertically coincide with one another. Thethree support columns 15 are fixed to the bottom disk 17 while beingarrayed semi-circularly. In this case, the wafer support portions 16protruded on the support columns 15 are adapted to be directed to theinside of the ring-like plate 13 in the diameter direction. The supportcolumns 15 are fitted to the notches 20 of the plural ring-like plates13 fixed temporarily, and the support columns 15 thus fitted are fixedto the ring-like plates 13 by the notched portions. Each of thering-like plates 13 is fixed so as to be located at a just intermediateportion between the plural wafer support portions 16 providedvertically. The top disk 11 is fixed to the columns 15. When the jig isdetached, the boat in which the large number of wafers are stacked atthe multi-stages is completed. Note that fixing of the boat members,which includes the fixing of the ring-like plates 13, is performed bymutual welding of quartz glass. No particular limitations are imposed onmaterials of the ring-like plates, the support columns, the top disk,and the bottom disk (that is, materials constituting the boat 217) aslong as the materials are heat-resistant. However, besides the quarts,heat-resistant materials such as silicon carbide (SiC), alumina (Al₂O₃)and ceramics are preferable.

Even if the ring-like plates are used, each of the wafer supportportions and the support columns adversely affects the film thickness ofthe wafers. In this case, if the wafer support portions are attachedonto the ring-like plates, and the wafer support portions are scatteredso as not to be superposed on the support columns, then the notches areprovided on the inner circumferential surfaces of the ring-like plateson the periphery of the attached portions of the wafer support portions,thus making it possible to reduce the adverse effect of the wafersupport portions. However, since the notches are not ones to reduce theadverse effect of the support columns, it is impossible to reduce theadverse effect of the support columns even with the notches.

From this viewpoint, according to this embodiment, the wafer supportportions are provided on the support columns, and the wafer supportportions and the support columns, each of which adversely affects thefilm thickness of the wafers, is thus integrated together. In addition,the notches are provided on the inner circumferential surfaces of thering-like plates on the periphery of the attached portions of the wafersupport portions, onto which the support columns are fitted.Accordingly, as compared with the case of scattering the wafer supportportions and the support columns, it is made possible to collectivelyreduce the adverse effect to be given to the film thickness from both ofthe wafer support portions and the support columns.

Incidentally, the reason why the wafer mounting portions have not beenheretofore provided on the support columns is as follows.

At the beginning, a substrate holder called a normal boat has been usedas one to mount the wafers at the multi-stages. The normal boat has ashape in which grooves (wafer mounting portions) are provided on pluralsupport columns arranged in an arc shape. Accordingly, at the time ofthe film forming, the film thickness on the periphery of the supportcolumns has tended to be thinned owing to the effect of the supportcolumns, and the film thickness of the peripheral edges of the wafers,where there are no support columns, has tended to be thickened.

In this connection, for the purpose of reducing the effect of thesupport columns to the film thickness, there has been proposed the ringboat, in which the rings having the support claw portions for mountingthe wafers provided thereon are laid on the normal boat, and the wafersare made apart from the support columns. Specifically, the ring boat isone in which the wafer mounting portions are transferred from thesupport columns to the rings. In order to reduce the effect of thesupport columns to the film thickness of the films on the wafers on theperiphery of the support claw portions, the support claw portions areprovided at spots going around the support columns. By adopting the ringboat, it has been made possible to make an improvement to thicken thefilm thickness of the portions on the periphery of the support columns,which has been thinned in the normal boat. Moreover, it has been madepossible to make an improvement to thin the film thickness of theperipheral edges of the wafers, where there are no support columns.

However, in the ring boat, though it has been made possible to make theimprovement to thin the film thickness of the peripheral edges of thewafers, where there are no support columns, the flow of the gas on theperiphery of the support claw portions has become nonuniform owing tothe effect of the support claw portions provided on the rings, causing anew problem that the film thickness of the wafers on the periphery ofthe support claw portions is thinned too much. Moreover, thenonuniformity of the gas flow owing to the effect of the support columnscannot be solved completely. Although the film thickness on theperiphery of the support columns of the ring boat has been improved tosome extent since the film thickness has been thickened as compared withthat of the normal boat, it cannot be said that a degree of theimprovement has been sufficient, and the film thickness on the peripheryof the support columns of the ring boat has been still thin as comparedwith the film thickness of the other portions.

As described above, in the normal boat, in which the grooves areprovided on the support columns, and the wafers are thus supported, theeffect of the support columns to the film thickness is large. In orderto avoid the effect, a concept of the ring boat is to make the wafersapart from the support columns by arranging the rings in the inside ofthe support columns and mounting the wafers on the rings. Hence, theboat of the type adopting the rings is one proposed based on the conceptto transfer the wafer support portions from the support columns to therings.

As described above, in this embodiment, the wafer support portions 16are fixedly attached onto the support columns, and the support columnsand the wafer support portions which are two main factors of the adverseeffect given to the film thickness of the wafers are thus integratedtogether. Accordingly, the adverse effect to the film thickness of thewafers can be reduced. Moreover, the inner circumferential surfaces ofthe ring-like plates 13 in the vicinities of the support columns arenotched. Accordingly, the effect of the support columns 15 and the wafersupport portions 16 to the gas flow is suppressed in the portions wherethe support columns 15 and the wafer support portions 16 are present,and it has been made possible to obtain, on the wafers 200, a similarfilm thickness to that in the portions where the wafer support portions16 and the support columns 15 are not present.

A description will be specifically made of the above by using FIG. 8.FIG. 8 is conceptual views of the gas flow when the processing gas flowsin a direction from the wafers 200 to the ring-like plates 13 and isexhausted downward in the case where the processing gas flows across theinner tube. FIG. 8(a) shows the gas flow in the portion where thesupport column 15 and the wafer support portions 16 are not present, andFIG. 8(b) shows the gas flow in the portion where the support column 15and the wafer support portions 16 are present. It is common knowledgethat a film-forming reaction by the processing gas occurs even on thesurface of quartz in the CVD processing and the like. However, owing tothe fact that the processing gas to originally react on the wafers 200reacts on the surface of quartz, an amount of the processing gassupplied to the wafer portions in the vicinities of the support columns15 and the wafer support portions 16 is reduced. As a result, the filmthickness of the wafer portions in the vicinities of the support columns15 and the wafer support portions 16 tends to be thinned.

In this embodiment, the notches 20 are provided on the ring-like plates13, and in FIG. 8, a distance LB between each wafer end and each supportcolumn 15 in the portions where the support columns 15 and the wafersupport portions 16 are present is made larger than a distance Labetween each wafer end and each inner circumferential surface of thering-like plates 13 in the portions where the support columns 15 and thewafer support portions 16 are not present, and conductance is thus madelarge. Thus, the amount of the processing gas flowing in the portionswhere the support columns 15 and the wafer support portions 16 arepresent is increased, thus making it possible to equalize a filmthickness of each wafer peripheral edge Wb in the portions where thesupport columns 15 and the wafer support portions 16 are not present anda film thickness of each wafer peripheral edge Wa in the portions wherethe support columns 15 and the wafer support portions 16 are present toeach other.

Note that, though the description has bee made of the case where theprocessing gas flows in the direction from the wafers 200 to thering-like plates 13 when the processing gas flows across the inner tubein FIG. 8, the above description can also be applied to the case wherethe processing gas flows in a direction from the ring-like plates 13 tothe wafers, and to the case where the processing gas flows upward fromthe bottom.

Hence, no matter whether the processing gas flows in the inner tube 204upward from the bottom or flows across the inner tube 204, theabove-described requirement to enhance the uniformity of the filmthickness in the wafer surfaces can be coped with. Moreover, the pluralring-like plates are provided on the support columns at thepredetermined interval in the vertical direction, and accordingly, theuniformity of the film thickness among the surfaces of the plural waferscan also be improved.

Moreover, as shown in FIG. 8, with regard to a relationship in verticaldistance between each ring-like plate 13 and each wafer 200, since theprocessing gas is supplied to flow between an upper surface of eachwafer and a lower surface of each ring-like plate disposed above thewafer 200, for example, when a distance between the upper surface of thewafer and the lower surface of the ring-like plate disposed above thewafer 200 is small, the gas directly hits on the ring-like plate, andthe gas becomes prone to be disturbed, thus adversely affecting theuniformity of the film thickness. Hence, it is preferable to make anarrangement so that the distance between the upper surface of the waferand the lower surface of the ring-like plate disposed above the wafer200 can be large. In particular, as shown in FIG. 9, when an arrangementis made so that the upper surface of the wafer and the upper surface ofthe ring-like plate can coincide with each other, that is, can be flushwith each other, the uniformity of the in-plane film thickness becomesmuch better. Moreover, a high film-forming rate can be maintained, thatis, the film-forming rate can also be improved.

FIG. 10 shows a comparison result from an evaluation on the film formingby the boat with the conventional shape shown in FIG. 15 and FIG. 16 andthe boat with the shape of this embodiment, which is shown in FIG. 1 andFIG. 2. In this evaluation, targets thereof were three wafers located onthree spots which are the top (TOP), center (CTR), and bottom (BTM) ofthe boat 217 among the plural wafers mounted on the boat 217. The filmthicknesses of the wafers after being subjected to the CVD processing,which were located at these positions, were measured, and the in-planeuniformities were obtained. An axis of abscissas represents thepositions of the wafers, and an axis of ordinates represents thein-plane uniformities. In the boat with the conventional shape, the filmthicknesses were thin in the portions of the support claw portions andthe support columns, and the in-plane uniformities were approximately2.0%. As opposed to this, in the boat with the shape of this embodiment,the effect of the wafer support portions and the support columns wassuppressed, and the in-plane uniformities were approximately 1%, whichwas a good result.

Note that film-forming conditions such as a gas type, a gas amount, apressure, a temperature, and a time at the time of performing theevaluation are silane (S1H4) of 400 cc, phosphine (PH3) of 50 cc, thepressure at 300 Pa, the temperature in the processing chamber at 530°C., and the film-forming time (deposition time) for 30 min for a DPOLYfilm (doped polysilicon film). The evaluation shows the results when thedistance La between the ring-like plate 13 and the wafer 200 in theportion where the support column is not present, which is shown in FIG.8(a), is equal to 4 mm, and when the distance Lb between the supportcolumn 15 and the wafer 200 in the portion where the support column 15is present, which is shown in FIG. 8(b), is equal to 8.5 mm.

Moreover, when the optimum value of La was evaluated by an experiment,in a film-forming evaluation of a wafer with a diameter of 300 mm, itwas found that the film thickness of the wafer peripheral edge becamethinner than the film thickness of the wafer center when La was lessthan 2 mm, and that, on the contrary, the film thickness of the waferperipheral edge became thicker than the film thickness of the wafercenter when La exceeded 7 mm. From this fact, it can be said that 2 to 7mm is the optimum as the distance La when the diameter of the wafer is300 mm. Moreover, it is essential that Lb be larger than La. This isbecause it is necessary to increase the conductance of a gas passage onthe side where the support columns 15 and the wafer support portions 16,which become obstacles to the gas flow, are present.

Note that, in the above-described embodiment, as shown in FIG. 7(a),each support column 15 fitted to the notch 20 is formed into thecolumnar shape, however, the shape of the support column 15 is notlimited to the columnar shape. The shape of the support column 15 justneeds to be a shape, in which the notches 20 are not embedded in thesupport columns 15, the openings 20 b in the vicinities of the fixedportions of the wafer support portions 16 are ensured, and the flow rateof the processing gas flowing in the vicinities of the support columns15 and the wafer support portions 16 is increased. For example, as shownin FIG. 7(b) and FIG. 7(c), a cross section of a support column 19 maybe formed into an approximately semi-columnar shape, and the wafersupport portion 16 may be attached onto the center of the semi-circle.Moreover, the wafer side of the cross section of the support column maybe formed into a scooped out shape. In this case, as shown in FIG. 7(d),even if the support column 19 is formed into an approximate half-pipeshape, and the wafer support portion 16 is protruded on a concave sidethereof, a similar effect can be obtained.

Moreover, preferably, as shown in FIG. 7, the wafer support portion 16is located on the center (vertically symmetrical in FIG. 7) of thesupport column 15 or 19 or the notch 20. Then, the effect can beobtained more.

Moreover, in this embodiment, each wafer support portion 16 is fixedlyattached onto the support column 15, and accordingly, it is easy toachieve accuracy on the wafer mounting position. This is because each ofa pair of the support column 15 and the wafer support portion 16 and apair of the support column 15 and the bottom disk 17 can be weldedtogether by bringing surfaces thereof in which the accuracy is achievedby machining into contact with each other. In terms of this point, it isdifficult to achieve the accuracy of the wafer mounting position in theone of the conventional example, which is shown in FIG. 16. In manycases, for the above-described conventional one, there is adopted a stepof polishing the surface of the holder plate 33 into a mirror surface,and attaching the support claw portion 34 thereonto with pressure (amethod of joining mirror-surfaced members to each other while applyingheat and force thereto) in the case of joining each support claw portion34 to the holder plate 33. Accompanied with the above, for the holderplate 33, for example, a step of polishing a raw material with athickness of 3 mm into a mirror-surface plate with a thickness of 2 mmis inevitably introduced. This is the reason why it is difficult toachieve the accuracy in the conventional example. Moreover, since theone of the conventional example requires the above-described steps, ithas taken an extremely long time to fabricate the same, and cost thereofhas also been high. As opposed to this, in this embodiment, what to dois only to fixedly attach each wafer support portion to the supportcolumn, and to join each ring-like plate with a simple structure, wherethere are no wafer support portions, to the support column on which thewafer support portion is provided. Accordingly, the above-describedsteps can be omitted, the fabrication time can be shortened to a greatextent, and the cost reduction can be realized.

Moreover, the wafer support portions 16 are fixedly attached onto thesupport columns 15, thus making it possible to set the number of supportcolumns 15 at three that is the minimum number capable of holding thewafers 200 in a symmetrical shape. In order to prevent the gas flow fromaffecting the wafers, it is necessary to provide the support columns 15at the positions symmetrical with respect to the center line of thering-like plates 13. In this embodiment, as shown in FIG. 1(b), thesupport column 15 can be provided to be stacked on each wafer supportportion 16 provided on the opposite side to the loading/unloading sideof the wafers on the center line of the ring-like plates 13. This is thereason why the number of support columns 15 can be set at three. Hence,in the case of providing the wafer support portions 16 on the supportcolumns 15, the number of portions in which the gas flow affects eachwafer can be set at three that is the minimum. Moreover, the number ofwafer support portions 16 is set at three, and the wafer can be thusheld by three-point support, thus making it possible to stably supportthe wafer.

Moreover, in the conventional holder boat, the support claw portions 14and each wafer have been brought into surface contact with each other,and sliding therebetween and the like when the wafer is inserted hascaused the generation of the particles. Moreover, in the case of the CVDprocessing and the like, since the surface contact has been brought inthe contact portions of the support claw portions 14 with the wafer, ithas been impossible to form the film on the back surface of the wafer.Therefore, a distortion owing to heat has occurred between the portionsubjected to the film forming and the portion that is not subjected tothe film forming on the back surface of the wafer, causing exfoliationof the film.

In terms of this point, in this embodiment, as shown in FIG. 5, thefixing angle of each columnar wafer support portion 16 is set parallelto the wafer, and the tip of the wafer support portion 16 is rounded orchamfered to make the contact surface into a line, and accordingly, theparticles generated owing to the sliding can be reduced to a greatextent. Moreover, since the contact portion of the support claw portions14 with the wafer makes the line contact, the region of the back surfaceof the wafer, which cannot be subjected to the film forming, can bereduced. Therefore, the distortion generated owing to the heat betweenthe portion subjected to the film forming and the portion that is notsubjected to the film forming on the back surface of the wafer can bereduced, and factors causing a damage to the wafer itself and theexfoliation of the film can be reduced.

Moreover, as shown in FIG. 6, when the fixing angle of each columnarwafer support portion 16 is inclined downward by θ, the wafer and thewafer support portion 16 are brought into point contact with each other,and accordingly, the particles can be further reduced.

Moreover, the boat of this embodiment can improve the uniformity of thefilm thickness in the wafer surface by the simple configuration in whichthe wafer support portions are provided on the support columns.Accordingly, the size of the boat is not increased, and the size of theapparatus is not increased, either. Hence, the deterioration of thethroughput owing to an excessive amount of heat is eliminated.

Note that, though the substrate processing apparatus of the presentinvention is particularly suitable for the vertical apparatus, thesubstrate processing apparatus is also applicable to the other substrateprocessing apparatuses. Moreover, with regard to the target film type,the substrate processing apparatus is naturally applicable over thegeneral CVD film including a D-POLY film, a Si3N4 film, a HTO film (ahigh-temperature oxidation film), and the like. Besides the above, thesubstrate processing apparatus is also applicable to an annealingfurnace, a diffusion furnace, and the like. In particular, the substrateprocessing apparatus of the present invention can enhance the depositionrate of the CVD film from the conventional 20 Å/min to 50 Å/min.Accordingly, the substrate processing apparatus is effective in terms ofa method of enhancing the deposition rate. Moreover, the substrateprocessing apparatus can enhance the uniformities of the inside of thewafer surface, between the wafer surfaces, and between the batches towithin ±1% from ±3% of the conventional substrate processing apparatususing the normal boat or the ring boat. Accordingly, the substrateprocessing apparatus of the present invention is effective also in termsof a method of enhancing the wafer quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is explanatory views of a ring-like plate according to anembodiment: FIG. 1(a) is a side view of main portions of a boat, inwhich attention is paid to one ring-like plate; and FIG. 1(b) is a planview of the ring-like plate including support columns.

FIG. 2 is an entire configuration view of the boat as a substrate holderaccording to the embodiment.

FIG. 3 is a perspective view showing a periphery of the support columnin a vicinity of a wafer support portion according to the embodiment.

FIG. 4 is a perspective view showing the periphery of the support columnin the vicinity of the wafer support portion according to a modificationexample of the embodiment.

FIG. 5 is an explanatory view showing a state where the boat accordingto the embodiment mounts wafers thereon.

FIG. 6 is an explanatory view showing a state where a boat according toa modification example of the embodiment mounts the wafers thereon.

FIG. 7 is plan views of main portions in the vicinities of supportcolumn portions, showing modification examples of a support column shapeaccording to the embodiment: FIG. 7(a) is an explanatory view showing amodification example in a case where the support column is columnar;FIG. 7(b) and FIG. 7(c) are explanatory views showing modificationexamples in a case where cross sections of the support columns areapproximately semi-circular; and FIG. 7(d) is an explanatory viewshowing a modification example in a case where the support column islike a half pipe.

FIG. 8 is explanatory views showing gas flows according to theembodiment: FIG. 8(a) is an explanatory view showing a gas flow in aportion where the wafer support portions and the support column are notpresent; and FIG. 8(b) is an explanatory view showing a gas flow in aportion where the wafer support portions and the support column arepresent.

FIG. 9 is explanatory views showing a gas flow according to theembodiment: FIG. 9(a) is an explanatory view showing a gas flow in aportion where the wafer support portions and the support column are notpresent; and FIG. 9(b) is an explanatory view showing a gas flow in aportion where the wafer support portions and the support column arepresent.

FIG. 10 is a comparison chart of uniformities of thin film thicknessesin the wafers between processing using the boat of the embodiment andprocessing using a boat of a conventional example.

FIG. 11 is a perspective view showing an entire configuration of asemiconductor manufacturing apparatus as a substrate processingapparatus according to the embodiment.

FIG. 12 is a longitudinal cross-sectional view of a reaction furnaceincluding controlling computers according to the embodiment.

FIG. 13 is explanatory views each showing a relationship between the gasflow and a distance between an inner tube and the ring-like plate in acase where processing gas according to the embodiment flows across theinner tube: FIG. 13(a) shows a case where a gap t between the inner tubeand an outer diameter of the boat is small; and FIG. 13(b) shows a casewhere the gap is large.

FIG. 14 is a configuration diagram of the first rolling computeraccording to the embodiment.

FIG. 15 is explanatory views of a holder plate of the conventionalexample: FIG. 15(a) is a side view; and FIG. 15(b) is a plan view.

FIG. 16 is an entire configuration view of the boat of the conventionalexample.

EXPLANATION OF REFERENCE NUMERALS

-   13 RING-LIKE PLATE-   15 SUPPORT COLUMN-   16 WAFER SUPPORT PORTION (SUBSTRATE MOUNTING PORTION)-   200 WAFER (SUBSTRATE)-   201 PROCESSING CHAMBER-   207 HEATER (HEATING MEANS)-   217 BOAT (SUBSTRATE HOLDER)-   232 GAS SUPPLY PIPE (GAS SUPPLYING MEANS)

1. A substrate processing apparatus, comprising: a substrate holdercapable of holding plural substrates; a processing chamber which housesthe substrates held by the substrate holder; heating means for heatingthe processing chamber; and gas supplying means for supplying processinggas to the processing chamber heated by the heating means, therebyprocessing the substrate, wherein the substrate holder includes: atleast three support columns provided substantially vertically; pluralsubstrate mounting portions which mount the plural substratessubstantially horizontally at a predetermined interval, the substratemounting portions being provided at multi-stages on the support columns;and plural ring-like plates arranged on the support columns, andprovided substantially horizontally at a predetermined interval withrespect to the substrates supported on the substrate mounting portions.2. The substrate processing apparatus according to claim 1, wherein thesubstrate mounting portions are columnar or approximately semi-columnarin cross section.
 3. The substrate processing apparatus according toclaim 2, wherein the substrate mounting portions are inclined downwardtoward an inside of the ring-like plates in a diameter direction.
 4. Thesubstrate processing apparatus according to claim 1, wherein innercircumferential surfaces of the ring-like plates, the innercircumferential surfaces being opposite to the support columns, arenotched on a periphery of the support columns.
 5. The substrateprocessing apparatus according to claim 4, wherein the substratemounting portions are columnar or approximately semi-columnar in crosssection.
 6. The substrate processing apparatus according to claim 5,wherein tips of the substrate mounting portions are rounded orchamfered.
 7. The substrate processing apparatus according to claim 6,wherein the substrate mounting portions are inclined downward toward aninside of the ring-like plates in a diameter direction.
 8. The substrateprocessing apparatus according t claim 4, wherein the support columnsare composed into an approximately semi-columnar shape in cross section,and the substrate mounting portions are protruded on a chord side of thesupport columns.
 9. The substrate processing apparatus according toclaim 8, wherein, on the chord side, an inside thereof in a diameterdirection of the ring-like plates is scooped out.
 10. The substrateprocessing apparatus according to claim 4, wherein the support columnsare provided more inside than outer circumferences of the ring-likeplates.
 11. A substrate processing apparatus, comprising: a substrateholder capable of holding plural substrates; a processing chamber whichhouses the substrates held by the substrate holder; heating means forheating the processing chamber; and gas supplying means for supplyingprocessing gas to the processing chamber heated by the heating means,thereby processing the substrate, wherein the substrate holder includes:at least three support columns provided substantially vertically; andplural ring-like plates which surround the at least three supportcolumns, are provided at multi-stages on the support columns, and areprovided substantially horizontally at a predetermined interval withrespect to the substrates held by the substrate holder, and innercircumferential surfaces of the ring-like plates, the innercircumferential surfaces being opposite to the support columns, arenotched on a periphery of the support columns.
 12. The substrateprocessing apparatus according to claim 11, wherein the support columnsare composed into an approximately semi-columnar shape in cross section,and the substrate mounting portions are protruded on a chord side of thesupport columns.
 13. The substrate processing apparatus according toclaim 11, wherein the support columns are provided more inside thanouter circumferences of the ring-like plates.
 14. The substrateprocessing apparatus according to claim 12, wherein, on the chord side,an inside thereof in a diameter direction of the ring-like plates isscooped out.
 15. A substrate holder capable of holding pluralsubstrates, comprising: at least three support columns providedsubstantially vertically; plural substrate mounting portions which mountthe plural substrates substantially horizontally at a predeterminedinterval, the substrate mounting portions being provided at multi-stageson the support columns; and plural ring-like plates arranged on thesupport columns, and provided substantially horizontally at apredetermined interval with respect to the substrates supported on thesubstrate mounting portions.
 16. The substrate holder according to claim15, wherein inner circumferential surfaces of the ring-like plates, theinner circumferential surfaces being opposite to the support columns,are notched on a periphery of the support columns.
 17. A substrateholder capable of holding plural substrates, comprising: at least threesupport columns provided substantially vertically; and plural ring-likeplates which surround the at least three support columns, are providedat multi-stages on the support columns, and are provided substantiallyhorizontally at a predetermined interval with respect to the substratesheld by the substrate holder, wherein inner circumferential surfaces ofthe ring-like plates, the inner circumferential surfaces being oppositeto the support columns, are notched on a periphery of the supportcolumns.
 18. A method of manufacturing a semiconductor device, themethod using a substrate processing apparatus including: a substrateholder capable of holding plural substrates; a processing chamber whichhouses the substrates held by the substrate holder; heating means forheating the processing chamber; and gas supplying means for supplyingprocessing gas to the processing chamber heated by the heating means,thereby processing the substrate, in which the substrate holderincludes: at least three support columns provided substantiallyvertically; plural substrate mounting portions which mount the pluralsubstrates substantially horizontally at a predetermined interval, thesubstrate mounting portions being provided at multi-stages on thesupport columns; and plural ring-like plates arranged on the supportcolumns, and provided substantially horizontally at a predeterminedinterval with respect to the substrates supported on the substratemounting portions, the method comprising the steps of: mounting thesubstrates on the substrate mounting portions of the substrate holder;carrying the substrates mounted on the substrate mounting portions ofthe substrate holder into the processing chamber; heating the processingchamber by the heating means; and supplying the processing gas to theheated processing chamber, thereby processing the substrate.